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New Zealand

Stockton Mine

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Summary

Mine TypeOpen Pit
StatusActive
Commodities
  • Coal (metallurgical)
  • Coal (thermal)
Mining Method
  • Truck & Shovel / Loader
Production Start... Lock
Mine Life... Lock
SnapshotStockton is the largest opencast mine in New Zealand, producing low-ash metallurgical coal that is exported overseas for use in steelmaking.

The Fast-Track Approval application being prepared for a submission in the first half of FY26 includes the Stockton Extension Project which will provide an extension of the Stockton mining permits, access arrangements and other approvals. This allows the site to continue to operate beyond 2027 and provides access to the Mount Fredrick South resource.

Stockton requires blending with the Buller Project to achieve 15 years at an average of 300ktpa.

The Buller Project encompasses mining and exploration permits, as well as a coal mining licence (Sullivan) on the Denniston Plateau. The project is located close to the Stockton mine and benefits from the use of Stockton’s infrastructure assets which include a coal handling and preparation plant, coal transport infrastructure and rail loadout facilities.

Owners

SourceSource
CompanyInterestOwnership
Talley’s Energy Ltd. 35 % Indirect
Bathurst Resources Ltd. 65 % Indirect
BT Mining Ltd. (operator) 100 % Direct
Stockton and Upper Waimangaroa are owned by BT Mining Limited. BT Mining Limited is a joint venture between Bathurst Resources Limited (65%) and Talley’s Energy Limited (35%). Bathurst Resources Ltd currently operates Stockton Opencast Mine.

Deposit type

  • Sedimentary

Summary:

Coal resources on the Stockton Plateau are restricted to the Middle to Late Eocene aged Brunner Coal Measures (BCM). The BCM unconformably overlies the Ordovician aged Greenland Group greywackes and argillites, which has been extensively intruded by Cretaceous granites and porphyry (Berlins Quartz Porphyry). Due to the stratigraphic nature of coal measures, the coal seams generally lie in a horizontal or sub-horizontal plane. The resource has a dip to the northeast at the northern end of the deposit and to east along the western margin. Folding and faulting through the coal seams can create localised changes in dips up to 80°.

Stockton
The Mangatini coal seams are the main coal seams of the Stockton deposit. The seams have been given the abbreviation M. There are the three seams M1, M2, and the M3. The M2 seam is the predominant seam over the deposit and splits into four segregated seams in places. The M1 seam is thin and discontinuous stratigraphically below the M2 and not considered for resource estimation. The M3 is a rider seam to the M2 however the seam is discontinuous and often not recovered during mining. The M3 is not considered during resource estimation.

Dimensions
The Stockton resource area covers approximately 22.9km², a roughly rectangular shape up to 3.5km wide (E-W), and 8km long (N-S).

Within this area all seams are exposed in the operating mine, with in situ coal between 0m and 50m below the original ground surface.

Coal thickness varies considerably over the deposit, from 28m (areas with structural thickening) down to <0.5m (areas with coal seam poorly developed). On average the remaining coal resource has an average thickness of 8-10m.

The M3 rider seam to the main M2 seams is on average 0.5m thick but can have localthicknesses of 3m.

Upper Waimangaroa
The Mangatini coal seams are the main coal seams of the Upper Waimangaroa Deposit. The seams have been given the abbreviation M. There are the three seams M1, M2, and the M3. The M1 and M2 seams are the predominant seams over the deposit. Seam splitting is commonacross the deposit and can lead t correlation complications. No distinct marker horizons arepresent between the seam. Correlations are based on detailed cross sections completed across the deposit. The M1 and M2 seams are the dominant seams targeted for mining and can vary in thickness. The M2 seam overlies the M1 seam. The M3 is a rider seam to the M2. The M3 seam is considered for resource classification in the Cypress consented area where it exceeds the minimal mining cut-off of 0.5m. The M3 seam is characterised by having high sulphur (>4%) and is generally poorly developed.

Dimensions
The Upper Waimagaroa resource area covers approximately 4km², a roughly rectangular shape up to 2km wide (ESE-WNW), and 10km long (NNE-SSW).

Within this area all seams are exposed at outcrop along the western margin of the MP. With the bulk of the in situ coal between 0 and 150m below the original ground surface.

Coal thickness varies considerably over the deposit, from over 20m (areas with structural thickening) down to <3m (areas with coal seam poorly developed). On average the cumulative (M1 and M2) coal resource has an average thickness of 8m.

The M3 seam is on average 0.5m thick.

Reserves

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Mining Methods

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Heavy Mobile Equipment

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Comminution

Crushers and Mills

Milling equipment has not been reported.

Processing

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Water usage

Parameter2025202420232022
Total water 836 ML715 ML782 ML871 ML

Commodity Production

CommodityUnits20252024202320222021202020192018
Coal (metallurgical) kt  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1,100970
All production numbers are expressed as clean coal.

Operational metrics

Metrics20252024202320222021202020192018
Annual processing capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe
Waste  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe3.65 Mbcm2.9 Mbcm

Production Costs

Commodity production costs have not been reported.

Mine Financials

Units20252024202320222021202020192018
Revenue M NZD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
Pre-tax Income M NZD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
After-tax Income M NZD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe
EBITDA M NZD  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe 103.7   105.9  

Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Nov 10, 2025
....................... Subscription required ....................... Subscription required Subscription required Nov 10, 2025
....................... Subscription required ....................... Subscription required Subscription required Nov 10, 2025

Workforce

EmployeesYear
...... Subscription required 2023
...... Subscription required 2017

Aerial view:

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